(1) Field of the Invention
This invention relates to a method for manufacturing carpet tiles exhibiting very small dimensional instability with respect to changes in ambient temperature.
(2) Description of the Prior Art
Carpet tiles are pieces of carpet in the shape of a square, rectangle, rhombus or the like or of a more complicated shape, having an area of, for example, 0.05 to 2 m.sup.2. Such carpet tiles may be positioned next to each other to closely cover a floor. Carpet tiles have an advantage over ordinary carpets in that they may be easily laid on floor by merely placing the carpet tiles side by side and fixing them. Carpet tiles also have the merit that they can provide a variety of visual impressions by using different combinations of shape and color, and the repair thereof is easy. In cases where the carpet tiles are laid on the floor, it is required that they adhere sufficiently to the floor so that no portion thereof slips from its appropriate position when one walks thereon. In this connection, carpet tiles are known which may be fixed by their own weight, such carpet tiles being designed to have a sufficient weight for flexibility (self-fixing) by comprising a relatively thick backing material.
Backing materials for carpet tiles serve also for providing fiber-shedding prevention, shape retaining performance, fitness onto floor and other various properties to the carpet tiles.
A conventional carpet tile has generally a construction in which a backing material is laminated on a carpet based material, and onto which a fabric backing is further optionally attached. There is also the case where an adhesive is used for fixing pile yarns of such carpet base material, or the case where no fabric backing is employed.
While conventional carpet tiles have the various advantages described above, there is also a disadvantage in that the dimension of such a conventional carpet tile changes slightly with changes in temperature due to changing of the seasons or rapid change in temperature due to air-conditioner. Since the carpet tile self-fixing characteristic property is its own weight, such carpet tiles have been usually applied without utilizing any adhesive means. For this reason, conventional carpet tiles have had the disadvantage in that if there is a significant change in temperature, considerable deformation is observed in a large area of application, even though there is a slight change in the dimension of a piece of carpet tile. In other words, when the temperature dropped remarkably, gaps appear between the respective carpet tiles due to slight shrinkage of them, so that it mars the beauty thereof, or the feel in case of walking on such shrunk carpet tiles becomes uncomfortable because these carpet tiles may slip out of place against one another at the time of such walking. On the contrary, when the temperature rises significantly, there is also the where bulges (swellings) are produced on the carpet tiles due to swelling thereof. It may be said that the most significant disadvantage of carpet tiles is the dimensional change thereof as a result of change in temperature as described above, so that immediate solution of such problem has been required.